HTTP
HTTP developer tools: convert cURL to 9 languages, header builders/parsers, cookies, auth, bodies, status codes, cache, CSP & security headers, CORS, compression (gzip/deflate), plus OpenAPI/Postman/HAR viewers — all in your browser.
Authentication
Auth header builders: Basic, Bearer, API Key, OAuth, Digest.
API Key Builder Online
Build an API key header or query parameter with a custom name. Free, fast, and runs entirely in your browser.
Basic Auth Builder Online
Build a Basic Authorization header from a username and password (Base64). Free, fast, and runs entirely in your browser.
Bearer Token Builder Online
Build a Bearer Authorization header from a token. Free, fast, and runs entirely in your browser.
Digest Auth Builder Online
Assemble the Digest Authorization header form from its parameters. Free, fast, and runs entirely in your browser.
OAuth Header Builder Online
Build an OAuth Authorization header from an access token (Bearer/MAC/DPoP). Free, fast, and runs entirely in your browser.
Body
Request body builders: JSON, form-data, urlencoded, multipart, query string.
Form Data Builder Online
Build an application/x-www-form-urlencoded body from key=value. Free, fast, and runs entirely in your browser.
JSON Body Builder Online
Build a JSON body from key=value pairs (value types are detected). Free, fast, and runs entirely in your browser.
Multipart Builder Online
Build a multipart/form-data body with a boundary from key=value. Free, fast, and runs entirely in your browser.
Query String Builder Online
Build a URL query string from parameters (with an optional base URL). Free, fast, and runs entirely in your browser.
URL-Encoded Builder Online
Build URL-encoded data with correct character escaping. Free, fast, and runs entirely in your browser.
Cache
Cache-Control builder/parser, ETag, and Expires.
Cache-Control Builder Online
Assemble a Cache-Control header from directives (max-age, public, no-store, …). Free, fast, and runs entirely in your browser.
Cache-Control Parser Online
Parse a Cache-Control value into readable directives. Free, fast, and runs entirely in your browser.
ETag Generator Online
Generate an ETag header from content for conditional caching. Free, fast, and runs entirely in your browser.
Expires Builder Online
Produce a cache-expiry directive from a duration (seconds). Free, fast, and runs entirely in your browser.
Compression
Native gzip & deflate compress/decompress, plus compression ratio.
Compression Ratio Online
Compare gzip vs deflate compression ratios for your text. Free, fast, and runs entirely in your browser.
deflate Inspector Online
Compress or decompress deflate data right in the browser (native). Free, fast, and runs entirely in your browser.
gzip Inspector Online
Compress or decompress gzip data right in the browser (native). Free, fast, and runs entirely in your browser.
Content Type
MIME lookup, Content-Type builder, and Accept header builder.
Accept Header Builder Online
Assemble an Accept header with automatic q-values (priority). Free, fast, and runs entirely in your browser.
Content-Type Builder Online
Assemble a Content-Type header with charset and boundary. Free, fast, and runs entirely in your browser.
MIME Type Lookup Online
Look up the MIME type for a file extension (.json → application/json). Free, fast, and runs entirely in your browser.
CORS
CORS header builder, preflight simulator, and config analyzer.
CORS Config Analyzer Online
Analyze response CORS headers and flag invalid configurations. Free, fast, and runs entirely in your browser.
CORS Header Builder Online
Assemble CORS headers (Access-Control-Allow-*) for server responses. Free, fast, and runs entirely in your browser.
CORS Preflight Simulator Online
See the OPTIONS preflight request a browser would send. Free, fast, and runs entirely in your browser.
cURL
Convert cURL to 9 languages, builder/parser, plus fetch/axios ⇄ cURL.
Axios Builder Online
Generate Axios request code from a URL, method, headers, and body. Free, fast, and runs entirely in your browser.
Axios to cURL Online
Turn a Axios snippet into an equivalent cURL command. Free, fast, and runs entirely in your browser.
cURL Builder Online
Assemble a cURL command from a URL, method, headers, body, and auth. Free, fast, and runs entirely in your browser.
cURL Parser Online
Break a cURL command into its method, URL, headers, and body. Free, fast, and runs entirely in your browser.
cURL to Axios Online
Convert a cURL command into ready-to-use Axios code — right in your browser. Free, fast, and runs entirely in your browser.
cURL to C# Online
Convert a cURL command into ready-to-use C# code — right in your browser. Free, fast, and runs entirely in your browser.
cURL to Fetch Online
Convert a cURL command into ready-to-use Fetch code — right in your browser. Free, fast, and runs entirely in your browser.
cURL to Go Online
Convert a cURL command into ready-to-use Go code — right in your browser. Free, fast, and runs entirely in your browser.
cURL to Java Online
Convert a cURL command into ready-to-use Java code — right in your browser. Free, fast, and runs entirely in your browser.
cURL to Node.js Online
Convert a cURL command into ready-to-use Node.js code — right in your browser. Free, fast, and runs entirely in your browser.
cURL to PHP Online
Convert a cURL command into ready-to-use PHP code — right in your browser. Free, fast, and runs entirely in your browser.
cURL to Python Online
Convert a cURL command into ready-to-use Python code — right in your browser. Free, fast, and runs entirely in your browser.
cURL to Rust Online
Convert a cURL command into ready-to-use Rust code — right in your browser. Free, fast, and runs entirely in your browser.
Fetch Builder Online
Generate JavaScript fetch() code from a URL, method, headers, and body. Free, fast, and runs entirely in your browser.
Fetch to cURL Online
Turn a Fetch snippet into an equivalent cURL command. Free, fast, and runs entirely in your browser.
HAR
HAR (HTTP Archive) file viewer, analyzer, and parser.
HAR Analyzer Online
Analyze a HAR file: total requests, size, time, and status/type breakdown. Free, fast, and runs entirely in your browser.
HAR Parser Online
Parse a HAR file into a list of request/response entries. Free, fast, and runs entirely in your browser.
HAR Viewer Online
View the request list from a HAR (HTTP Archive) file. Free, fast, and runs entirely in your browser.
Header
Header parser, builder, formatter, analyzer, cheat sheet, and HTTP version.
HTTP Header Analyzer Online
Analyze response headers and check for missing security headers. Free, fast, and runs entirely in your browser.
HTTP Header Builder Online
Assemble an HTTP header block from Key=Value pairs. Free, fast, and runs entirely in your browser.
HTTP Header Cheat Sheet Online
A quick reference of common HTTP headers and what they do. Free, fast, and runs entirely in your browser.
HTTP Header Formatter Online
Normalize HTTP header name casing to the canonical Title-Case form. Free, fast, and runs entirely in your browser.
HTTP Header Parser Online
Parse a block of HTTP headers into clean name–value pairs. Free, fast, and runs entirely in your browser.
HTTP Version Lookup Online
Learn the differences between HTTP/0.9, 1.0, 1.1, 2, and 3. Free, fast, and runs entirely in your browser.
OpenAPI
OpenAPI/Swagger spec viewer, parser, and validator (JSON/YAML).
OpenAPI Parser Online
Parse an OpenAPI spec into a structured endpoint list. Free, fast, and runs entirely in your browser.
OpenAPI Validator Online
Check the basic structure of an OpenAPI/Swagger document. Free, fast, and runs entirely in your browser.
OpenAPI Viewer Online
View a summary of an OpenAPI/Swagger spec: info and endpoint list. Free, fast, and runs entirely in your browser.
Postman
Postman collection viewer and conversion to cURL.
Security
CSP, HSTS, Permissions-Policy, Referrer-Policy, X-Frame-Options builders.
CSP Builder Online
Assemble a Content-Security-Policy header from source directives. Free, fast, and runs entirely in your browser.
CSP Parser Online
Parse a Content-Security-Policy into its directives and sources. Free, fast, and runs entirely in your browser.
HSTS Builder Online
Assemble a Strict-Transport-Security (HSTS) header to force HTTPS. Free, fast, and runs entirely in your browser.
Permissions-Policy Builder Online
Assemble a Permissions-Policy header to control browser features. Free, fast, and runs entirely in your browser.
Referrer-Policy Builder Online
Pick a Referrer-Policy value to control what referrer info is sent. Free, fast, and runs entirely in your browser.
X-Frame-Options Builder Online
Build an X-Frame-Options header to prevent clickjacking. Free, fast, and runs entirely in your browser.
Status Code
HTTP status code lookup, explorer, and category.
HTTP Status Code Category Online
View all status codes in one class (1xx–5xx). Free, fast, and runs entirely in your browser.
HTTP Status Code Explorer Online
A full list of every HTTP status code with its name. Free, fast, and runs entirely in your browser.
HTTP Status Code Lookup Online
Look up the meaning of an HTTP status code (200, 301, 404, 500, …) with an explanation. Free, fast, and runs entirely in your browser.
Utilities
Request-ID generator and User-Agent builder.